Fluid valves

ABSTRACT

There is disclosed a family of check and/or pressure relief fluid valve utilizing a spring biased annular diaphragm element for valving. In a single-function form there is disclosed a simple check valve. In a dual-function form there is disclosed a check valve also having a pressure relief function permitting reverse flow above a predetermined pressure differential, this form being disclosed in an automotive fuel tank filler tube cap (i.e. a &#39;&#39;&#39;&#39;gas cap&#39;&#39;&#39;&#39;). There is also disclosed an improved filler tube cap construction and seal therefor. In a multifunction form there is disclosed a fluid valve capable of relieving a source of fluid under pressure to a primary outlet at a first very low pressure and additionally to a secondary outlet at a higher pressure. This valve also acts as a check valve by preventing the pressure of the fluid source from dropping below that at the secondary outlet. There is also disclosed an arrangement for using this multifunction valve in an evaporative emission control system for a motor vehicle having an internal combustion engine. All of the valves disclosed are particularly suited for gaseous fluids.

United States Patent 1191 Sheppard FLUID VALVES [76] Inventor: WilliamL. Sheppard, 36655 Romulus Rd., Romulus, Mich. 48174 [22] Filed: May 18,1972 [2]] Appl. No.: 254,655

Related U.S. Application Data [63] Continuation-impart of Ser. No.65,773, Aug. 2|,

1970, abandoned.

52 u.s.c1. 137/525, 137/5255 51 1111. C1. Fl6k 15/14 58 Field of Search137/525, 512.15, 512.4, 137/5156, 516.15, 525.5

[56] References Cited UNITED STATES PATENTS 3,073,339 l/l963 Stelzerl37/5l6.15

3,194,262 7/1965 Hamilton et al. 137/525 X 3,580,273 5/1971 Sehwarz137/525 3,646,956 3/1972 Rodgers 137/525 Primary Examiner-William R.Cline Attorney, Agent, or FirmHarness, Dickey & Pierce Aug. 6, 1974 5 7ABSTRACT There is disclosed a family of check and/or pressure relieffluid valve utilizing a spring biased annular diaphragm element forvalving. In a single-function form there is disclosed a simple checkvalve. In a dualfunction form there is disclosed a check valve alsohaving a pressure relief function permitting reverse flow above apredetermined pressure differential, this form being disclosed in anautomotive fuel tank filler tube cap (Le. a gas cap). There is alsodisclosed an improved filler tube cap construction and seal therefor. Ina multifunction form there is disclosed a fluid valve capable ofrelieving a source of fluid under pressure to a primary outlet at afirst very low pressure and additionally to a secondary outlet at ahigher pressure. This valve also acts as a check valve by preventing thepressure of the fluid source from dropping below that at the secondaryoutlet. There is also disclosed an arrangement for using thismultifunction valve in an evaporative emission control system for amotor vehicle having an internal combustion engine. All of the valvesdisclosed are particularly suited for gaseous fluids.

15 Claims, 14 Drawing Figures PATENTEBAUG 5:974

SHEET 8 [IF Q PAIENTEB 61974 3,82'h456 SHEET 0F 4 FLUID VALVES REFERENCETO COPENDING APPLICATION This application is a continuation-in-part ofapplicants co-pending application Ser. No. 65,773, filed Aug. 21, 1970entitled Fluid Valve, now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION give relatively high sealingforces. The possible uses for the single-function check valve arevirtually unlimited, however it has been found to be ideal in vacuumcontrol systems for automotive heating and air conditioning systems. Themultifunction form of the valve of this invention is particularly suitedfor use in an evaporative emission control system for a motor vehiclehaving an internal combustion engine. The primary function ofevaporative emission control systems is to eliminate or reduce thequantity of undesirable hydrocarbon fuel vapors which evaporate to theatmosphere from the fuel system, usually through the vents which arenormally provided. In such an application the valve inlet is connectedto the fuel tank, the primary outlet to the engine, either directly orthrough a cannister of activated charcoal in accordance with knownpractice, and the secondary outlet to the atmosphere or a secondaryreceptacle, either directly or through an adsorbing medium in accordancewith the present invention. When vapor pressures start to build up inthe fuel tank the primary pressure relief section of the present valve,which is responsive to extremely small pressure differentials (i.e.,less than 0.2 psig), opens to permit such vapors to accumulate in theengine (crankcase and/or air cleaner) or a charcoal loaded cannister viathe primary outlet. This prevents the vapors from going into theatmosphere. In most systems vapors which accumulate when the engine isnot running are purged by intake manifold vacuum when the engine isstarted, so that capacity is recreated for accumulating vapors when theengine is again stopped. In practice it has been found that undercertainconditions (extreme heat, etc.) the quantity of vapor evaporatingin the fuel tank is so great that the primary system cannot handle them,and as a consequence pressure builds up in the fuel tank. This isundesirable because it may rupture the tank or if repeated may causeseams to crack and leak. The secondary pressure relief section of thepresent valve prevents this by opening when the pressure differentialreaches a potentially injurious level to permit suchexcessive vapors toescape from the tank via the secondary outlet, in addition to theprimary outlet. In known systems the secondary outlet communicatesdirectly with the atmosphere, however one aspect of the presentinvention resides in communicating such excessive vapors to an auxiliaryreceptacle such as the interior of a box section of the vehicle frame,either directly or via an adsorbing medium disposed either inside oroutside the hollow frame section. Should the pressure in the tank everdrop below atmospheric (such as might be due to rapid cooling, action ofthe fuel pump, etc.) collapsing of the tank and/or flexing cracks areprevented by the check valve function of the present valve which causesit to open in response to an extremely small negative pressure condition(e.g. l inch water column) in the tank to place the latter incommunication with the atmosphere via the secondary outlet.

The dual-function form of the present valve is also particularly suitedfor an evaporative emission control system, but one which is lesssophisticated than the one described above. In this simpler system,venting of the fuel tank to atmosphere takes place through the cap forthe tank filler tube. The valve is disposed in the cap and has apressure relief function which operates to prevent venting unless thevapor pressure in the tank exceeds atmospheric by some predeterminedvalue (high enough to eliminate most unnecessary venting, but low enoughto prevent pressure damage to the tank or fuel system). It also has acheck valve function which is responsive to the existence of even anextremely small negative pressure in the tank to place it incommunication with the atmosphere, as does the multifunction valve.Another aspect'of this invention concerns the provision of an improvedgas cap construction having improved sealing means.

Primary objects of the present invention reside in the provision of afamily of relatively simple and inexpensive valves having the aforesaidcharacteristics and functions, which valves are responsive to extremelysmall positive or negative pressure differentials and yet remain fullyand reliably closed until conditions call for opening.

Another importantobject of the present invention concerns the provisionof a family of very sensitive diaphragm-type valves which will closewithout pressure reversal and which incorporate means preventingoverstressing or extrusion of the diaphragm itself.

Another important object of the present invention resides in theprovision of a very sensitive check valve which will open in response toextremely small pressure differentials, in the order of several inchesof water, and yet which will not leak when subjected to relatively largepressure reversals, in the order of one atmosphere or more.

Another important object of the present invention resides in theprovision of a multifunction valve in which the primary and secondarypressure relief functions are accomplished by essentially two reliefvalves in series, whereby the secondary valve remains fully closed untilthe primary valve is fully open, and one which is not responsive topressures downstream of the primary outlet.

Another important object of the present invention resides in theprovision of an evaporative emission control system in which secondaryvapors are not communicated directly to the atmosphere.

Another important object of the present invention resides in theprovision of an extremely simple and inexpensive technique for mountingto a motor vehicle such a valve for an evaporative emission controlsystem.

Another important object of the present invention resides in theprovision of extremely simple and highly efficient sealing means forvalves.

Another important object of the present invention resides in theprovision of a very sensitive dual function valve of the type describedwhich will fit within a conventional fuel tank filler tube cap.

Another important object of the present invention resides in theprovision of a fuel tank filler tube cap having improved sealing means.

Other objects, features and advantages of the present invention willbecome apparent from the subsequent description and the appended claims,taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectionalview of a multifunction valve embodying the principles of the presentinvention;

FIG. 2 is an end view thereof;

FIG. 3 is a sectional view taken along the line 33 in FIG. 1;

FIGS. 4, 5 and 6 are enlarged fragmentary views illustrating the valveunder different operating conditions;

FIG. 7 is an enlarged fragmentary sectional view of a portion of thevalve;

FIG. 8 is a diagrammatical illustration of a manner in which the valvecan be incorporated into an evaporative emission control system;

FIG. 9 is a longitudinal sectional view of a dualfunction valveembodying the principles of the present invention and incorporated in afuel tank filler tube cap;

FIG. 10 is a sectional view taken along line l010 in FIG. 9;

FIG. 11 is a sectional view taken along line llll in FIG. 9;

FIG. 12 is a longitudinal sectional view of a simple check valveembodying the principles of the present invention;

FIG. 13 is a sectional view taken along line 13-13 in FIG. 12; and

FIG. 14 is a sectional view taken along line 14l4 in FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although themultifunction valve of the present invention is believed to have generalutility, it is known to be particularly suited for use in motor vehicleevaporative emission control systems and therefore will be describedherein in such a system.

The multifunction valve, indicated generally at 10, comprises a firsthousing element 12 having an inlet tubing or hose nipple 14 containingan inlet passageway 16, and a second housing element 18 having a primaryoutlet hose nipple 20 containing primary outlet passageway 22 and asecondary outlet passageway 26. Housing elements 12 and 18 are generallyhollow, defining a cavity in which is disposed a resilient or flexiblediaphragm of circular configuration in plan having a relatively stiffcentral section containing a center passageway 32, an annular flexiblesection 34 extending outwardly from central section 30 and a peripheralsealing bead section 36. The diaphragm divides the housing cavity intoseparate cavities 35 and 37, inlet passageway 16 communicating directlywith cavity 35.

Housing elements 12 and 18 are provided with complementary opposedannular recesses 38 and re-' spectively (FIG. 7) which receive in asealing manner bead portion 36 when the two housing elements are as--sembled to one another. The housing elements are dimensioned so thatelement 18 may be easily inserted within element 12 withoutinterference, recesses 38 and 40 being provided with annular shoulders39 and 41 respectively so that when the elements are assembled with bead36 in place they snap over the resilient bead and are held assembled bythe engagement of the bead with shoulders 39 and 41. Bead 36 not onlyholds the parts together but it seals cavities 35 and 37 from oneanother and from the atmosphere at the juncture of the housing elements.Element 18 is provided with a rounded annular ridge 42 which urgessection 34 of the diaphragm against a complementary fiat surface 44 onelement 12, whereby the diaphragm is secured against movement along acircular line which lies in a single plane and is concentric with thecenter of the diaphragm. All sections of the diaphragm are generallysymmetrical about and concentric with such axis, which as used hereinconstitutes the center axis or axis of movement of the valve means.

Central section 30 of the diaphragm has formed on one side thereof aflat transverse annular surface 46 adapted to engage a compressionspring 48 which operates between it and a complementary parallel surface50 on housing element 12, and on the other side thereof a fiattransverse annular valve surface 52 and a plurality of lugs 54 havingflat stop surfaces 56 lying in a common transverse plane (FIG. 6).

Formed integrally with housing element 18 along said center axis is afluted projection 58 having rigidly secured to the free end thereof by asuitable fastening device 60 (FIG. 6) a circular stop member 62 having aplurality of holes 64 therein and a fiat transversely extending surface66 extending parallel to and in alignment with stop surfaces 56 on thediaphragm. Spring 48 urges the diaphragm toward the right as shown.Projection 58 also has fixedly secured thereto adjacent the stop membera resilient valve member 68 having a valve surface 70 lying in a flattransverse plane (FIG. 5). Stop member 62 is constructed so that theflow of fluid through holes 64 is not blocked by valve member 68 or lugs54 on the diaphragm when it engages the stop member.

Also disposed in cavity 37 is a cup-shaped element 72 having a centerbore 74 (FIG. 5) loosely surrounding and guided by projection 58. Asbest seen in FIG. 5, the

outer rim of element 72 is provided with a rounded an.

nular valve surface 76 adapted to sealingly engage valve surface 52 onthe diaphragm (together they constitute the secondary valve), and thecenter portion of cup element 72 is provided with an annular valvesurface 78 adapted to sealingly engage valve surface 70 on valve member68 (together they constitute the primary valve).

As best seen in FIG. 4, cup element 72 and housing element 18 areprovided with complementary opposed projecting cylindrical shoulders 80and 82, respectively, against the cornersdefined by which are sealinglyengaged the circular end beads 84 and 86 of a flexible bellows 88. Bead84 is urged in place by a conical washer 90 and bead 86 by a conicalwasher 92. A compression spring 94 urges washer 90 toward cup element 72and washer 92 towardhousing element 18 to cause the olique surfaces onthe washers to urge the beads into a sealing engagement, primarily withthe cylindrical portions of the shoulders because their shape is moreeasily controlled. Assembly of the bellows is easily affected by merelycollapsing the spring-andwasher-bellows assembly with a suitable tool,placing one end over shoulder 82, inserting shoulder 80 of the cupelement into the other end, mounting valve element 68 in place, and thenreleasing the spring to permit it to expand to urge each bead intosealing engagement with its corresponding shoulder.

Spring 94 also biases cup element 72 toward valve element 68 and thediaphragm. Thus, in the normal or at rest condition of the valve, spring94 urges valve surface 78 into sealing engagement with valve surface 70and spring 48 urges valve surface 52 into sealing engagement with valvesurface 76. In that condition of the valve stop surfaces 56 are spacedfrom stop member 62, as is shown in FIG. 1.

The flow of inlet fluid through the valve to the primary outlet is frominlet passageway 16 through center passageway 32, holes 64, across theprimary valve defined by valve surfaces 70 and 78, between the flutes ofprojection 58 and bore 74 into the chamber defined by bellows 88, whichis in direct fluid communication with outlet passageway 22. Secondaryinlet fluid flows from inlet passageway 16 through central passageway 32and the secondary valve defined by surfaces 76 and 52 directly intosecondary outlet passageway 26. Although the inlet fluid ispredominantly gaseous, a liquid-air froth or even small amounts ofliquid fuel may pass through the valve.

The inlet pressure which acts to open the primary valve is that whichacts on the effective area of the diaphragm less the closed effectivearea of the primary valve (i.e., that defined by the outside diameter ofvalve element 68). Spring 94 is chosen to give the desired openingpressure relief setting for the primary valve for the size valve used,subject to corrections for theforces applied by spring 48, the diaphragmitself, and the bellows itself. The pressure which acts to open thesecondary valve is that which acts on the effective area within valvesurface 76, less the open effective area of the primary valve (which isgreater than defined by the diameter of bore 74 but less than the closedeffective area, depending on how far open the valve is). The desiredopening pressure relief setting for the secondary valve is thus achievedby choosing the'desired diameters and hence areas. Spring 48 ispreferably just sufficiently strong to hold valve surface 52 on thediaphragm sealingly against valve surface 76 in the presence ofatmospheric pressure in the inlet passageway.

The present valve is ideally suited to high volume production techniquesbecause of the relative simplicity of its design and method of assembly.For example, the housing elements may be molded from nylon, thecup-shaped element from Delrin, and the diaphragm bellows and valvemember from a suitable elastomer such as an epichlorohydrin rubber.Washers 90 and 92 and stop member 62 may be stamped sheet metal.Fastening device 60 may consist merely of a spun or mashed titintegrally formed on the end of projection 58.

In FIG. 8 there is diagrammatically illustrated a novel technique forusing the multifunction valve in an evaporative emission control systemfor a motor vehicle. The inlet nipple is connected to a hose 106 whichconnects to the top of the fuel tank (not shown), and the primary outletnipple is connected to a hose 108 which connects to either the motorvehicle engine, cannister of activated charcoal or other primaryaccumulator in accordance with the practices of known systems. In priorsystems the secondary'outlet of the control valve normally vented toatmosphere. This of course meant that in the event an excessive vapor orpressure condition occurred, causing the secondary outlet to function,fuel vapors and sometimes liquid fuel would be dumped directly into theatmosphere or onto the street, as the case may be. In accordance withone aspect of the present invention, however, housing element 18 isprovided with a projecting portion having an annular groove 110 adaptedto be inserted into a conventional f rubber grommet in a suitablylocated opening in the box section 102 of the usual frame of a motorvehicle. This arrangement not only provides an extremely simple andinexpensive way of mounting the present valve in such a system, but alsoresults in there being provided an auxiliary recepticle (i.e., thehollow interior 104 of the box section) in which the excess vapors andpossibly small portions of liquid fuel can accumulate. Housing element18 is provided with a conical surface 112 adjacent groove to facilitateinsertion of the valve into the grommet. Additionally, the normallyempty space 104 within the box frame may be filled (between suit ablebarriers if desired) with activated charcoal, whereby additional meansare provided for accumulating and/or adsorbing excess fuel vapors or thelike. It is contemplated that the frame section would not be sealed fromthe atmosphere (conventional construction), so that the secondary outletwill always be at atmospheric pressure.

The operation of the present valve will be described in connection withits use in an evaporative emission control system although thecharacteristics of its operation are applicable to other environments.In its normal at rest condition (atmospheric pressure at the inlet andboth outlets) the valve is as shown in FIG. 1 with both the primary andsecondary valves closed. When pressure starts to build in the fuel tankit will bias the diaphragm to the right as shown in FIG. I, which inturn will cause cup-shaped element 72 to move to the right therebyopening the primary valve to permit the fuel vapors, etc., to flow frominlet passageway 16 into primary outlet passageway 22 and thence to theengine or a cannister, depending on the particular system in which thevalve is utilized. Because of the relatively large effective areaoffered by the diaphragm spring 94 and the diameter of the primary valvemay be chosen to render the valve responsive to an extremely smallincrease in pressure above atmospheric. For example, pressure settingsof as low as 0.114 psig have been achieved. The movement of thediaphragm to the right is progressive with increasing pressure, as isthe opening of the primary valve, until surfaces 56 on lugs 54 engagestop surface 66 on stop member 62, in which condition the primary valveis fully open. This condition of the valve is shown in FIG. 4. Shouldthe pressure in the fuel tank build up to a value which exceeds thesetting of the primary valve cup-shaped element 72 (but not thediaphragm which is now against the stop) will be biased to the right bysuch excess pressure thereby opening the secondary valve. In condition,shown in FIG. 5, all inlet fluid which cannot flow through the primaryvalve will flow through the secondary valve to the secondary outlet.Thus, it can be seen that the primary and secondary valves operate in aseries with one another in that the secondary valve cannot begin to openuntil the primary valve is fully open.

This means that the secondary pressure relief setting will always behigher than that of the primary.

In the event a vacuum condition develops in the fuel tank, such as byrapid cooling or action of the fuel pump, such decreased pressure willcause the diaphragm to move to the left as shown in FIG. 6 to permitatmospheric air to flow through the secondary outlet and the secondaryvalve into the fuel tank. This eliminates the need for the normal gascap vent. Response to vacuums as small as 1 inch of water column havebeen achieved with the present valve.

A further advantage of the present valve is that the mean effective areaof bellows 88 may be made essentially the same as the mean effectivearea of the primary valve so that the presence of a vacuum or a pressurecommunicated to primary outlet passageway 22 will not itself influencethe valve in any way. In addition, the primary valve is designed withbuilt-in hysteresis, giving it stability. This arises from the fact thatthe effective area of the primary valve decreases when it opens, thuscausing it to close at a lower inlet pressure than that at which itopens, which in turn prevents hunting, noise and the like.

With reference to the dual-function embodiment of FIGS. 9-11, there isillustrated a fuel tank filler tube cap 200 incorporating a combinedtank vent and pressure relief valve embodying the principals of thepresent invention. The gas cap construction comprises a generallycylindrical outer shroud or shell 202 having closed end wall 204, agenerally cylindrical concentrically located internal cup element 206,and handle means including manually operable handle tabs 208 projectingaway from end wall 204 and having an integral retaining portion 210overlying such wall portion. The overall assembly may be fastenedtogether by means of a rivet-like fastener 212 in a manner to bedescribed. Cup element 206 is designed to fit within the conventionalfiller tube (not shown) of an automotive vehicle fuel tank and isprovided with conventional latching tangs 214 and 216, for locking thecap in the safety blow-off and the fully locked or sealed position, inaccordance with known practices. The overall cylindrical shape of cupelement 206 assists in the centering of the valve cap on the fillertube, and shell 202 overlies the outside of the free end of the fillertube to cover and protect same. The shell and cup element may beinexpensive metal stampings.

The upper end of cup element is generally closed by an outer annular endwall portion 218, a central end wall portion 220 and aninterconnectingportion 222. End wall portion 220 is provided with a plurality ofthrough holes 226. In addition, the central portion of end wall 204 ofthe shell is depressed slightly as indicated at 224 and provided with aplurality of outer through holes 228 placing the inside of the shell incommunication with the atmosphere, and a plurality of inner throughholes 230 aligned with holes 226 to place the interior of cup element206 in communication with the atmosphere. Depressed portion 224 isgreater in area than handle portion 210 so that the latter does notblock communication with holes 228 and 230.

In order to provide a seal between the top of the tiller tube (notshown) and the cap, there is provided a resilient, annular, generallyflat sealing element 232 having an enlarged bead portion 234 disposedabout its inner periphery and a downwardly projecting annular bead 234is generally circular in cross-sectional configuration when in therelaxed state, and is disposed between end wall portions 218 and 224 ina sealing relationship with respect thereto. The lower portion of thecrosssectional configuration of bead 236 is rounded in order to providea sealing surface adapted to sealingly engage the upper end of the fueltank filler tube. The upper surface of sealing element 232 may beprovided with a plurality of integral projections, one of which isindicated at 238, adapted to engage end wall 204 and thereby preventoverstressing of sealing element 232 if the cap is overtightened.Embedded within element 232 is a generally annular reinforcing andspring eleportion 236 about its outer periphery. Bead portion ment 240.Sealing element 232 is preferably formed from an elastomeric materialsuch as Bunu-N and has molded therein reinforcing element 240, which maybe of a suitable spring material such as silicone bronze. Reinforcingelement 240 is of the cross-sectional configuration illustrated in FIG.9, and as can be seen at 242 is provided with an upwardly projectingannular ridge which directly engages end wall 224. Reinforcing element240 thus maintains the sealing element in its at rest positionillustrated, acts as a biasing element to urge it sealingly against theend of the filler tube, and prevents it from wrinkling.

It has been noted above that projections 238 prevent overstressing ofsealing element 232 and reinforcing element 240 in the axial direction.Overstressing in the circumferential direction is also prevented to someextent by reinforcing element 240, but the general arrangement of theparts gives further protection, i.e., when the cap is torqued down onthe end of the filler tube to the point when the friction of bead 236therewith reaches a potentially damaging magnitude, inner bead 234(because of its smaller radius and hence smaller moment arm) will slideor rotate with respect to the remainder of the cap structure to preventcircumferential overstressing. This protection may be accomplished byproperly sizing bead 234 with respect to end wall portions 218 and 224,and portion 222 in accordance with known practices.

The basic valve cap as described up to this point is capable of fullysealing the open end of a conventional fuel tank filler tube, utilizingimproved sealing means. The only communication between the interior ofthe filler tube and the atmosphere, when the cap is installed, isthrough holes 226 and 230 thereof. The flow of fluid (e.g., fuel vaporand/or atmospheric air) through the holes is controlled by a valveindicated generally at 250 disposed within cup element 206 and supportedby fastener 212. As best seen in FIG. 9, the main shank portion offastener 212 is provided with an annular flange 252. The portion of theshank of fastener 212 disposed outwardly from flange 252, indicated at254, may be square in cross-section and presses through correspondinglyshaped holes in the end walls of cup element 206 and shell 202. Theseparts are rigidly connected together by deforming the end of portion 254into an enlarged head 256, in the same manner as a rivet. The squareshape of portion 254 and the openings through which it bases preventrelative rotation of the parts. The inner portion of the shank offastener 212, indicated at 256, may be circular in crosssectionalconfiguration and is provided with a first reduced diameter portion 258and a second reduced diameter portion 260, progressively.

Disposed about portion 258 is a valve seat 261 having a generally flatannular valve surface 262. Valve seat 261, which may be formed of asuitable elastomeric material, such as Buna-N, is held in place by meansof a retainer 264 having a plurality of through holes 266 and extendingoutwardly for the entire extent of the interior of cup element 206, theouter periphery of retainer 264 having an offset flange 268 disposedadjacent the inner wall of the cup element. Retainer 264, which may bean inexpensive metal stamping, is in turn held in place by forming theend of fastener portion 260 into an enlarged head 270, in the samemanner as a rivet.

Also disposed about portion 256 of fastener 212 is an annular valveelement 272 having a generally flat annular first valve surface 274 anda second relatively narrow annular valve surface 276 disposedconcentrically inwardly with respect thereto and adapted to sealinglyengage valve surface 262 on valve seat 261. Valve element 272, which maybe molded out of inexpensive plastic, such as polycarbonate, is providedwith an enlarged central passageway 278 which is larger than the portion256 of fastener 212 and is provided with a plurality of projections 280to keep the valve element loosely centered on fastener 212. Valveelement 272 is resiliently biased against valve seat 261 by means of acompression spring 282. Also disposed within cup element 206 is anannular retaining element 284 including an inwardly directed radialflange 286 engaging end wall portion 218, a cylindrical wall portion 288and a radially outwardly directed flange 290 having a reversely curlededge 292 presenting a smooth arcuate outer surface. Retaining element284 may be an inexpensive metal stamping. Sealingly disposed between theouter corner of end wall portion 218 of cup element 206 and portions 288and 290 of retaining element 284 is an enlarged outer peripheral bead294 of an annular diaphragm 296 having enlarged inner peripheral bead298 adapted to sealingly engage valve surface 274 on valve element 272.Beads 294 and 298 are generally circular in cross-section in the relaxedstate. Diaphragm 296 is formed from a suitable elastomer, such asepichlorohydrin or the like. Disposed between diaphragm 296 and flange268 of retainer 264 is the outer periphery of an annular washer-typespring 300 having a plurality of radially extending slits 302 andopenings 304 to increase the flexibility thereof, the inner periphery ofwhich is resiliently biased against the inner periphery of diaphragm 296to bias bead 298 into sealing engagement with valve surface 274. Spring300 may be formed of silicon bronze or like spring material, andpreferably exerts just sufficient force on the diaphragm to seat same.

The dual function valve of this embodiment functions in the followingmanner when affixed to the open end of a filler tube by means of a capof the construction illustrated. Since bead 298 normally engages valvesurface 274, since valve surface 276 normally engages valve seat 261 andsince the end of the filler cap is sealed by means of sealing element232, the escape of vapors is normally prevented from the fuel tank, asis the flow of atmospheric air into the tank. However,

. upon the creation of even a slight negative pressure 'in the tank withrespect to atmosphere and pressure differential will act across therelatively large area of diaphragm 296 and causes it to move away fromvalve ele- 'ment 272 against the very small bias of spring 300 to permitatmospheric air to flow into the tank through holes 230 and 226, acrossthe gap between bead 298 and valve surface 274, through the center valveopening in spring 300 and thence through holes 266 into the tank.Diaphragm 296 thus provides the check valve function of this valve.Pressure differentials in the opposite direction merely cause thediaphragm to seal more tightly. When the pressure in the tank reaches apredetermined differential with respect to atmospheric pressure,however, valve element 272 and diaphragm 296 move upwardly together inresponse thereto against the bias of spring 282, but assisted by thesmall bias of spring 300, to cause valve surface 276 to move away fromvalve surface 262 of valve seat 261, thereby permitting the exit ofvapor or the like from the fuel tank through holes 266, the gap betweenvalve seat 261 and valve element 272, passageway 278, and holes 226 and230 to atmosphere. The predetermined pressure differential at which thevalve will permit venting is determined by the rate of spring 282 andthe effective diameters of the valve seals and the elements responsiveto'actuating pressure, in accordance with established procedures.

With reference to the embodiment of FIGS. 12-14, there is illustrated acheck valve 400 comprising two joined housing sections 402 and 404,respectively, preferably inexpensively molded from plastic. Each ofthese sections is provided at its free end with an enlarged portion 404constituting a conventional nipple for receiving a hose or the like.Section 402 is provided with a through passageway 406 communicating witha chamber 408 within an enlarged portion 410, and section 403 with athrough passageway 412 communicating with a chamber 414 defined by anenlarged portion 416 which terminates in an annular portion 418 having arounded upper surface 420, a circumferential notch 422 around the outerperiphery and a square-cornered recess 424 about the inner periphery.Portion 410 of section 402 terminates in a cylindrical flange portion426 about the inner periphery of which is provided a flat annularshoulder 428 and a circumferential groove 430.

Disposed within recess 424 is a transversely arranged valve seat element432 comprising a centrally disposed imperforate portion 434 having onthe upper surface thereof (as shown in FIG. 12) a generally flat annularvalve seat 436. Element 424 is maintained in position by means of aplurality of outwardly radially extending spokes 438 the end of whichare disposed in recess 424 and secured to portion 418 by means of anadhesive, a press fit or the like. The spaces between spokes 438 areindicated at 440 and constitute passageways through which fluid may flowthrough the valve. Element 432 may also be inexpensively molded out ofplastic.

Disposed above element 432 is an annular imperforate flexible diaphragm442 having enlarged bead 444 about the inner periphery thereof definingan opening 446, and an enlarged bead 448 about the outer peripherythereof. Beads 444 and 448 are preferably generally circular incross-sectional configuration when in the relaxed state. Diaphragm 442is formed of a suitable elastomer, such as epichlorohydrin or the like.

Disposed above diaphragm 442 (as shown in FIG. 12) is a generallyannular substantially flat (when relaxed) washer-type spring 450 whichmay be formed of phosphor-bronze or like spring material. Spring 450 isprovided with 'a plurality of radially outwardly directed slits 4S2extending from the inner periphery thereof, indicated at 454. Slits 452may be provided with an enlarged cut-out portions 456, as best shown inFIG. 13, to increase the flexibilty thereof. Portions 456 are preferablyspaced from inner periphery 454 in order to provide a substantiallycontinuous annular surface on the spring adapted to bear on bead 444 ofdiaphragm 442.

The manner in which the valve is assembled is best illustrated in FIG.12. As can be seen, section 403 fits within section 402 so that recess430 lies in a generally facing opposed relationship to recess 422, andin the space defined thereby is disposed bead 448 of diaphragm 442. Bead448 thus serves not only to anchor the outer periphery of the diaphragmbut also to seal the former between sections 402 and 403 with respect tothe atmosphere and both sides of the diaphragm and further to hold thetwo housing sections together, in essentially the same manner as isshown and described with respect to FIG. 7. The outer portion of spring450 is pinched between the portion of the diaphragm lying on roundedsurface 420 and annular surface 428 and is so arranged that the innerperiphery thereof biases bead 444 against valve seat 436.

As can thus be seen, valve 400 is normally closed by virtue of thebiasing action of spring 450, preferably as weak as possible, howeverwhen the pressure in passageway 412 exceeds that of passageway 406 by anamount sufficient to overcome the relatively weak bias of spring 450,the diaphragm and its bead 444 will be forced away from valve seat 446to permit the flow of fluid through passageways 440, the space betweenbead 444 and valve surface 436, opening 446 and through the center ofspring 450 to passageway 406. The existence of a pressure in passageway406 greater than that in passageway 412 merely causes bead 444 to seatwith greater force upon valve surface 436, thereby preventing flow inthe downward direction as shown in FIG. 12. Passageways 440 arepreferably sufficiently narrow to eliminate the possibility of thediaphragm extruding through said passageways in the presence of highback pressure differentials.

Thus, there is disclosed in the above description and in the drawingsseveral exemplary embodiments of the invention which fully andeffectively accomplish the objects thereof. However, it will be apparentthat variations in the details of construction may be indulged inwithout departing from the sphere of the invention herein described, orthe scope of the appended claims.

I claim:

1. A fluid valve comprising: housing means having a passagewaytherethrough; valve seat means including an annular valve seat in saidpassageway and means preventing fluid flow through the area defined bysaid seat; elastomeric diaphragm means having a central openingtherethrough, said diaphragm means preventing the flow of fluid throughsaid passageway except through said opening; and means defining a beadof increased thickness about the periphery of said opening and anattaching portion adjacent the outer periphery of said diaphragm means,the entire intermediate portion of said diaphragm means disposed betweensaid bead and said attaching portion being relatively thin and flexibleas compared to said bead, said attaching portion being fixed withrespect to said housing means, the upstream portion of said bead beinggenerally circular in cross-section in a relaxed state and adapted tonormally sealingly engage said valve seat, said intermediate portion ofsaid diaphragm means joining said bead on the opposite side of a planedisposed parallel to said valve seat and spaced therefrom in thedownstream direction, said bead being movable away from said valve seatto permit the flow of fluid from one end of said passageway through saidopening in a downstream direction when the pressure at said one endexceeds the pressure at said other end.

2. A fluid valve as claimed in claim 1, wherein said valve seat is fixedin location with respect to said housing means.

3. A fluid valve as claimed in claim 1, wherein said valve seat ismovable with respect to said housing means.

4. A fluid valve as claimed in claim 1, further comprising spring meansnormally biasing said upstream portion of said bead into sealingengagement with said valve seat.

5. A fluid valve comprising: housing means having a passagewaytherethrough; valve seat means including an annular valve seat in saidpassageway and means preventing fluid flow through the area defined bysaid seat; elastomeric diaphragm means having a central openingtherethrough, said diaphragm means preventing the flow of fluid throughsaid passageway except through said opening; means defining a first beadof increased thickness about the periphery of said opening and a secondbead of increased thickness about the outer periphery of said diaphragmmeans, the entire portion of said diaphragm means disposed between saidtwo beads being relatively thin and flexible as compared to said beads,said first bead having an upstream portion which is generally circularin cross-section in a relaxed state; and spring means biasing saidupstream portion of said first bead against said valve seat into sealingengagement therewith, said spring means being relatively fiat when in arelaxed state and including a plurality of resilient fingers the freeends of which provide a substantially continuous annular surface bearingon said first bead, said diaphragm means and first bead being movableaway from said valve seat against the bias of said spring means topermit the flow of fluid from one end of said passageway through saidopening in a downstream direction when the pressure at said one endexceeds the pressure at said other end.

6. A fluid valve comprising: housing means having a passagewaytherethrough; valve seat means including an annular valve seat in saidpassageway and means preventing fluid flow through the area defined bysaid seat; elastomeric diaphragm means having a central openingtherethrough, said diaphragm means preventing the flow of fluid throughsaid passageway except through said opening; means defining a bead ofincreased thickness about the periphery of said opening, said beadhaving an upstream portion which is generally circular in cross-sectionin a relaxed state; and spring means biasing said upstream portion ofsaid bead against said valve seat into sealing engagement therewith,said spring means being relatively flat when in a relaxed state andincluding a plurality of resilient fingers the free ends of whichprovide a substantially continuous annular surface bearing on said bead,said diaphragm means and bead being movable away from said valve seatagainst the bias of said spring means to permit the flow of fluid fromone end of said passageway through said opening in a downstreamdirection when the pressure at said one end exceeds the pressure at saidother end.

7. A fluid valve as claimed in claim 6, wherein said valve seat isgenerally flat.

8. A fluid valve as claimed in claim 6, wherein said valve seat is fixedin location with respect to said housing means.

9. A fluid valve comprising: housing means having a passagewaytherethrough; valve seat means including an annular valve seat disposedin said passageway and supported in position by a support elementextending therefrom to said housing means, said element having aplurality of openings therethrough to permit fluid to flow therethrough,and means preventing fluid flow through the area defined by said seat;elastomeric diaphragm means having a central opening therethrough, saiddiaphragm means preventing the flow of fluid through said passagewayexcept through said opening; means defining a head of increasedthickness about the periphery of said opening; and spring means biasingsaid bead against said valve seat into sealing engagement therewith,said spring means being relatively flat when in a relaxed state, saiddiaphragm means and bead being movable in a downstream direction awayfrom said valve seat against the bias of said spring means to pennit theflow of fluid from one end of said passageway through said opening in adownstream direction when the pressure at said one end exceeds thepressure at said other end, said element having downstream surface meansfor preventing said diaphragm means from moving excessively far in anupstream direction when the pressure at said other end exceeds thepressure at said one end.

10. A fluid valve comprising: housing means having a passagewaytherethrough; valve seat means including an annular valve seat in saidpassageway and means preventing fluid flow through the area defined bysaid seat; elastomeric diaphragm means having a central openingtherethrough, said diaphragm means preventing the flow of fluid throughsaid passageway except through said opening; means defining a bead ofincreased thickness about the periphery of said opening; and springmeans biasing said bead against said valve seat into sealing engagement.therewith, said spring means comprising in an unstressed state arelatively flat disc of resilient material having a central hole and aplurality of radially outwardly extending slits extending therefrom topoints spaced from the outer periphery of said disc to thereby define aplurality of resilient fingers the free ends of which provide asubstantially continuous annular surface bearing on said bead, saiddiaphragm means and bead being movable away from said valve seat againstthe bias of said spring means to permit the flow of fluid from one endof said passageway through said opening when the pressure at said oneexceeds the pressure at said other end.

11. A fluid valve as claimed in claim 9, wherein said support elementcomprises a spoke-like member having spaced-apart spokes extendingbetween said valve seat and said housing means.

12. A fluid valve as claimed in claim 10, wherein said slits areprovided with cut-out portions to increase the flexibility of saidfingers.

13. A fluid; valve comprising: housing means having a passagewaytherethrough; valve seat means including an annular valve seat in saidpassageway and means preventing fluid flow through the area defined bysaid seat; resilient diaphragm means having a central openingtherethrough, said diaphragm means preventing the flow of fluid throughsaid passageway except through said opening, means defining a first beadof increased thickness about the periphery of said opening and a secondbead of increased thickness about the outer periphery of said diaphragmmeans, the entire intermediate portion of said diaphragm means disposedbetween said two beads being relatively thin and flexible compared tosaid beads; and spring means biasing the upstream portion of said firsthead against said valve seat into sealing engagement therewith, saidspring means being relatively flat when in a relaxed state and beingdisposed transversely to the flow of fluid through the valve, saidspring means having substantially the entirety of its upstream facedisposed against the downstream face of said intermediate portion ofsaid diaphragm means and including a plurality of resilient fingers thefree ends of which provide a substantially continuous annular surfacebearing on the downstream portion of said first bead, said diaphragmmeans and first bead being movable away from said valve seat against thebias of said passageway through said opening in a downstream directionwhen the pressure at said one end exceeds the pressure at said otherend.

14. A fluid valve as claimed in claim l3, wherein said upstream portionof said first bead is rounded in cross section so that it can roll onsaid valve seat and wherein clearance is provided between said valveseat and the juncture of said first bead and intermediate portionwhereby increased closing pressures acting on said intermediate portionwill cause said first bead to roll outwardly.

15. A fluid valve comprising: housing means having a passagewaytherethrough; valve seat means including 7 an annular valve seat in saidpassageway and means preventing fluid flow through the area defined bysaid seat; elastomeric diaphragm means having a central openingtherethrough, said diaphragm means preventing the flow of fluid throughsaid passageway except through said opening; means defining a bead ofincreased thickness about the periphery of said opening and an attachingportion adjacent the outer periphery of said diaphragm means, the entireintermediate portion of said diaphragm means disposed between said beadand said attaching portion being relatively thin and flexible ascompared to said bead, said attaching portion being fixed with respectto said housing means, said bead having a first annular surface normallysealingly engaging a second annular surface on said valve seat, one ofsaid first or second annular surfaces being generally flat and the otherbeing generally circular in cross-section, said bead being movable awayfrom said valve seat to permit the flow of fluid from one end of saidpassageway through said opening in a downstream direction when thepressure at one end exceeds the pressure at said other end; and supportmeans for supporting said valve seat means with respect to said housingmeans, said support means having a downstream face entirely spaced fromthe upstream face of said intermediate portion of said diaphragm meanswhen the latter is in a relaxed state whereby a rolling action willoccur between said valve seat and bead-when the pressure at said otherend exceeds the pressure at said one end by an amount sufficient tocause said intermediate portion to move towards said downstream face ofsaid support means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N 3. 827.456 Dated August a. 1974i Inventor(s William L. Sheppard It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 10, line 49 "end" should be "ends -Q Signed and sealed this 3rdday of December 1974.

(SEAL) Attest:

GIBSON JR. I c. MARSHALL DANN McCOY M.

Commissioner of Patents Attesting Officer USCOMM-DC GOING-P69 e u.s.GOVERNMENT PRINTING OFFICE: I959 0-366-334 FORM PO-1050(10-69)

1. A fluid valve comprising: housing means having a passagewaytherethrough; valve seat means including an annular valve seat in saidpassageway and means preventing fluid flow through the area defined bysaid seat; elastomeric diaphragm means having a central openingtherethrough, said diaphragm means preventing the flow of fluid throughsaid passageway except through said opening; and means defining a beadof increased thickness about the periphery of said opening and anattaching portion adjacent the outer periphery of said diaphragm means,the entire intermediate portion of said diaphragm means disposed betweensaid bead and said attaching portion being relatively thin and flexibleas compared to said bead, said attaching portion being fixed withrespect to said housing means, the upstream portion of said bead beinggenerally circular in cross-section in a relaxed state and adapted tonormally sealingly engage said valve seat, said intermediate portion ofsaid diaphragm means joining said bead on the opposite side of a planedisposed parallel to said valve seat and spaced therefrom in thedownstream direction, said bead being movable away from said valve seatto permit the flow of fluid from one end of said passageway through saidopening in a downstream direction when the pressure at said one endexceeds the pressure at said other end.
 2. A fluid valve as claimed inclaim 1, wherein said valve seat is fixed in location with respect tosaid housing means.
 3. A fluid valve as claimed in claim 1, wherein saidvalve seat is movable with respect to said housing means.
 4. A fluidvalve as claimed in claim 1, further comprising spring means normallybiasing said upstream portion of said bead into sealing engagement withsaid valve seat.
 5. A fluid valve comprising: housing means having apassageway therethrough; valve seat means including an annular valveseat in said passageway and means preventing fluid flow through the areadefined by said seat; elastomeric diaphragm means having a centralopening therethrough, said diaphragm means preventing the flow of fluidthrough said passageway except through said opening; means defining afirst bead of increased thickness about the periphery of said openingand a second bead of increased thickness about the outer periphery ofsaid diaphragm means, the entire portion of said diaphragm meansdisposed between said two beads being relatively thin and flexible ascompared to said beads, said first bead having an upstream portion whichis generally circular in cross-section in a relaxed state; and springmeans biasing said upstream portion of said first bead against saidvalve seat into sealing engagement therewith, said spring means beingrelatively flat when in a relaxed state and including a plurality ofresilient fingers the free ends of which provide a substantiallycontinuous annular surface bearing on said first bead, said diaphragmmeans and first bead being movable away from said valve seat against thebias of said spring means to permit the flow of fluid from one end ofsaid passageway through said opening in a downstream direction when thepressure at said one end exceeds the pressure at said other end.
 6. Afluid valve comprising: housing means having a passageway therethrough;valve seat means including an annular valve seat in said passageway andmeans preventing fluid flow through the area defined by said seat;elastomeric diaphragm means having a central opening therethrough, saiddiaphragm means preventing the flow of fluid through said passagewayexcept through said opening; means defining a bead of increasedthickness about the periphery of said opening, said bead having anupstream portion which is generally circular in cross-section in arelaxed state; and spring means biasing said upstream portion of saidbead against said valve seat into sealing engagement therewith, saidspring means being relatively flat when in a relaxed state and includinga plurality of resilient fingers the free ends of which provide asubstantially continuous annular surface bearing on said bead, saiddiaphragm means and bead being movable away from said valve seat againstthe bias of said spring means to permit the flow of fluid from one endof said passageway through said opening in a downstream direction whenthe pressure at said one end exceeds the pressure at said other end. 7.A fluid valve as claimed in claim 6, wherein said valve seat isgenerally flat.
 8. A fluid valve as claimed in claim 6, wherein saidvalve seat is fixed in location with respect to said housing means.
 9. Afluid valve comprising: housing means having a passageway therethrough;valve seat means including an annular valve seat disposed in saidpassageway and supported in position by a support element extendingtherefrom to said housing means, said element having a plurality ofopenings therethrough to permit fluid to flow therethrough, and meanspreventing fluid flow through the area defined by said seat; elastomericdiaphragm means having a central opening therethrough, said diaphragmmeans preventing the flow of fluid through said passageway exceptthrough said opening; means defining a bead of increased thickness aboutthe periphery of said opening; and spring means biasing said beadagainst said valve seat into sealing engagement therewith, said springmeans being relatively flat when in a relaxed state, said diaphragmmeans and bead being movable in a downstream direction away from saidvalve seat against the bias of said spring means to permit the flow offluid from one end of said passageway through said opening in adownstream direction when the pressure at said onE end exceeds thepressure at said other end, said element having downstream surface meansfor preventing said diaphragm means from moving excessively far in anupstream direction when the pressure at said other end exceeds thepressure at said one end.
 10. A fluid valve comprising: housing meanshaving a passageway therethrough; valve seat means including an annularvalve seat in said passageway and means preventing fluid flow throughthe area defined by said seat; elastomeric diaphragm means having acentral opening therethrough, said diaphragm means preventing the flowof fluid through said passageway except through said opening; meansdefining a bead of increased thickness about the periphery of saidopening; and spring means biasing said bead against said valve seat intosealing engagement therewith, said spring means comprising in anunstressed state a relatively flat disc of resilient material having acentral hole and a plurality of radially outwardly extending slitsextending therefrom to points spaced from the outer periphery of saiddisc to thereby define a plurality of resilient fingers the free ends ofwhich provide a substantially continuous annular surface bearing on saidbead, said diaphragm means and bead being movable away from said valveseat against the bias of said spring means to permit the flow of fluidfrom one end of said passageway through said opening when the pressureat said one exceeds the pressure at said other end.
 11. A fluid valve asclaimed in claim 9, wherein said support element comprises a spoke-likemember having spaced-apart spokes extending between said valve seat andsaid housing means.
 12. A fluid valve as claimed in claim 10, whereinsaid slits are provided with cut-out portions to increase theflexibility of said fingers.
 13. A fluid valve comprising: housing meanshaving a passageway therethrough; valve seat means including an annularvalve seat in said passageway and means preventing fluid flow throughthe area defined by said seat; resilient diaphragm means having acentral opening therethrough, said diaphragm means preventing the flowof fluid through said passageway except through said opening, meansdefining a first bead of increased thickness about the periphery of saidopening and a second bead of increased thickness about the outerperiphery of said diaphragm means, the entire intermediate portion ofsaid diaphragm means disposed between said two beads being relativelythin and flexible compared to said beads; and spring means biasing theupstream portion of said first bead against said valve seat into sealingengagement therewith, said spring means being relatively flat when in arelaxed state and being disposed transversely to the flow of fluidthrough the valve, said spring means having substantially the entiretyof its upstream face disposed against the downstream face of saidintermediate portion of said diaphragm means and including a pluralityof resilient fingers the free ends of which provide a substantiallycontinuous annular surface bearing on the downstream portion of saidfirst bead, said diaphragm means and first bead being movable away fromsaid valve seat against the bias of said passageway through said openingin a downstream direction when the pressure at said one end exceeds thepressure at said other end.
 14. A fluid valve as claimed in claim 13,wherein said upstream portion of said first bead is rounded incross-section so that it can roll on said valve seat and whereinclearance is provided between said valve seat and the juncture of saidfirst bead and intermediate portion whereby increased closing pressuresacting on said intermediate portion will cause said first bead to rolloutwardly.
 15. A fluid valve comprising: housing means having apassageway therethrough; valve seat means including an annular valveseat in said passageway and means preventing fluid flow through the areadefined by said seat; elastomeric diaphragm means having a centralopening therethrough, said diaphragM means preventing the flow of fluidthrough said passageway except through said opening; means defining abead of increased thickness about the periphery of said opening and anattaching portion adjacent the outer periphery of said diaphragm means,the entire intermediate portion of said diaphragm means disposed betweensaid bead and said attaching portion being relatively thin and flexibleas compared to said bead, said attaching portion being fixed withrespect to said housing means, said bead having a first annular surfacenormally sealingly engaging a second annular surface on said valve seat,one of said first or second annular surfaces being generally flat andthe other being generally circular in cross-section, said bead beingmovable away from said valve seat to permit the flow of fluid from oneend of said passageway through said opening in a downstream directionwhen the pressure at one end exceeds the pressure at said other end; andsupport means for supporting said valve seat means with respect to saidhousing means, said support means having a downstream face entirelyspaced from the upstream face of said intermediate portion of saiddiaphragm means when the latter is in a relaxed state whereby a rollingaction will occur between said valve seat and bead when the pressure atsaid other end exceeds the pressure at said one end by an amountsufficient to cause said intermediate portion to move towards saiddownstream face of said support means.